Portable speaker



FIG. 1 is a perspective view of a portable speaker according to our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a reduced perspective view thereof, connected to a cellular phone and another speaker while in use.

The broken line shown in the drawing is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a portable speaker, as shown and described. 